Serpent SER500904 Shock 13mm cap o-ring — shock cap o-ring for RC dampers  [SER500904]

Shock cap o-ring overview

The Serpent SER500904 Shock 13mm cap o-ring is a small-scale replacement sealing ring designed for use in RC shock cap assemblies. It serves the simple but important role of keeping oil inside the shock body and preventing dirt ingress at the cap interface, contributing to predictable damping behaviour.

Use this o-ring when the original seal shows signs of flattening, cracking, or oil leakage. Because it addresses sealing at the cap rather than piston or shaft interfaces, installation is straightforward and requires only basic disassembly of the shock cap from the shock body. Inspect the groove and cap surface for burrs before seating the o-ring to ensure a consistent seal.

For tuning and setup, a correctly seated 13mm cap o-ring helps maintain consistent oil levels and damping response between runs. If you are changing shock oil or adjusting spring preload, replace the cap o-ring as part of regular maintenance to avoid intermittent leaks that can affect lap-to-lap consistency.